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Ferrari 400i automatic transmission / acceleration problems

Discussion in '365 GT4 2+2/400/412' started by Art400i, Jun 13, 2021.

  1. Art400i

    Art400i Rookie

    Nov 16, 2013
    3
    On my car, I feel like the gears are slipping. There is no uniform acceleration. Feels like braking in between. Engine speed feels even. Transmission fluid is sufficiently full (Can it be too full?)
    The effect is extreme when I want to accelerate quickly and go full throttle. Less extreme when I accelerate very slowly. Does anyone have any tips on what it could be? Thanks all!
     
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  3. raemin

    raemin Formula Junior

    Jan 16, 2007
    880
    Lyon (FR)
    Full Name:
    R. Emin
    Performance torque converters are "loose" which alllws to free the engine and let it rev higher. So if you do not have the stock bulky converter, this is actually a performance upgrade. By contrast if then sleepage is not die to a converter change, your tranny/converter might be in need of an overhaul.
     
  4. SouthJersey400i

    SouthJersey400i Formula 3

    Mar 14, 2007
    1,379
    Romulus, NY (Finger Lakes)
    Full Name:
    Ken Battle
    Assuming you are in North America, find a GOOD transmission shop and have them do a test drive. There are more than 10 million TH400 transmissions out there. A shop that does drag racing will want to do an "upgrade" but for street driving stock is probably good for you. There is nothing that can't be fixed or replaced on that transmission.
    Ken
     
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  5. Theruse

    Theruse Rookie

    Jan 17, 2014
    26
    Maryland
    Full Name:
    Prescott Russo
    A simple and inexpensive job to do is to change the transmission filter. The filter and gasket are around $20-25. plus new transmission fluid. I would recommend you use a duraprene gasket. The filters can easily clog and if shifting gears gives you a heavy clunk rather than a smooth shift, oftentimes its a clogged filter.
     
  6. fez1238

    fez1238 Karting
    Silver Subscribed

    Sep 5, 2007
    170
    Yes the filter is the usual suspect. It can sometimes drop and come loose when going over bumps in the road. Inexpensive fix. Hope this helps.
     
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  8. Ak Jim

    Ak Jim F1 Veteran
    Rossa Subscribed Owner

    Dec 23, 2007
    5,736
    North Pole AK
    Avoid driving the car until you have either a competent shop look it over or you drop the pan and check the filter. Also if you do drop the pan I’m not sure if the pan on your car has a drain plug or not but if it does not then get an after market pan with a drain plug, it will make future work on the transmission be a lot less messy.
     

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